This is a nice idea, but I cannot stand sites that instantly launch an extension window (in my case, for Alby) asking me to finalize/confirm a connection request that I never personally initialized in the first place. It's obnoxious and bad form from a UI/UX perspective, not to mention just a dumb move to make as a developer, you're adding unnecessary amounts of outbound connection requests constantly upon loading the site.
Also, having to rely upon receiving an archive file from twitter of your own stuff instead of attempting to automatically bridge the content/mirror it seems kind of janky, especially since you'll have to wait to be "granted" your own stuff back from the corporate overlords at Twitter, errm, I mean "X", and who knows how long that'll take?
You might be able to accomplish the same thing even quicker yourself, using a scraping service like IFTTT to create a Google Sheets or Airtable collection of all of the tweets on your account, within a reasonable timeframe of course -- and then take that and upload it into such a site.
Heck, if something along these lines doesn't come along I might have to build it myself.